In top-quality timepieces, in particular in those where all or part of the movement is made visible, the winding ratchet comprises a square drive opening in which the end square of the barrel arbor is housed. This winding ratchet is then screwed in using three screws, generally into the terminal surface of the barrel arbor as it is depicted in FIG. 6.
This method is particularly aesthetic but involves the drawback of requiring a large-diameter barrel arbor that uselessly occupies a large volume of the inside space of the barrel cage, which makes it necessary to limit the length and the number of coils of the barrel spring for a barrel cage of a given diameter. The result is a reduction in the operating reserve or an increase in the diameter of the barrel cage and therefore the amount of space it requires. The result is also a weight increase of the barrel arbor.